Process of treating asbestos ore



Sept. 11, 1928. 1,684,365

- S. H. DOLBEAR PROCESS OF TREATING ASBESTOS ORE Filed June 2, 1924 2 Sheets-Sheet 1 Samaelliiflal6 Car,

Sept. 11, 1928.

S. H. DOLBEAR PROCESS OF 'IREATLNG ASBESTOS ORE Filed June 1924 2 Sheets-Sheet a w c v n I Ofzy utl/ f1. fol 60a 2',

Patented Sept. 11, 1928.

UNITED STATES PATENT OFFICE.

SAMUEL H. DOLIBEAR, OF NEW YORK, N. Y., ASSIGNOR TO SELECTIVE TREATMENT COMPANY LIMITED, OF MONTREAL, CANADA, A CORPORATION OF QUEBEC.

PROCESS OF TREATING ASBESTOS ORE.

Application filed June 2, 1924, Serial No. 717,385, and in Canada September 20, 1923.

This invention relates to a process of treating asbestos ore, the main object of the invention being to economically extract the fiber from the rock under such conditions of control that the character of the fiber, its length, texture, color, cleanliness, and other qualities may be predetermined as required.

A further object of the invention is to provide a method by means of which the ore will be treated in a liquid medium.

The general practice for the recovery of the fiber in asbestos-mills at present is a so-called dry-process. The ore is broken in primary crushers, such as jaw or gyratory crushers, to about 8"-size. It is then dried in rotary or vertical driers. The ore is then passed (in a dry condition) through hammer-crushers, rolls, disc-crushers, cyclones, or jumbo-fiberizers. This results in breaking up the rock and fiberizing, or flufiing. the fiber. These fiberizers usually operate at a speed of about 1800 R. P. M., the ore being beaten violently, thereby resulting in destructive breakage of the fiber. The value of the fiber varies according to length, the longer grades being more valuable than the shorter grades. Thus, the treatment given the ore in the machines employed in the dry-process cut the fiber into shorter lengths, thereby reducing the Value of the product. The rock is then passed over tables which are equipped with screens, at the lower edge of which is situated an air-suction and by which the fiber is sucked away from the rock. Aside from the destructive action on the fiber itself, a large amount of fiber is lost in this process, it being discharged with the rock, or floats away as dust during the process of treatment.

It has been discovered. and the present invention is predicated upon the discovery, that asbestos-ore may be suitably treated in liquid ."U as to minimize or avoid damage to the fiber, the fiber may then be separated in liquid from associated gangue, or rocky matter, and the fiber subsequently given suitable treatment, including drying, so as to produce asbestos of a highly satisfactory and desirable character, and a product in which the original length of fiber has been substantially preserved.

Furthermore, the fiber so produced is free from rock-dust, which oftentimes constitutes a substantial percentage of the dry-process product, and the amount of fiber recovered by my process is in excess of that recovered by such dry-process.

More specifically, my novel process herein described preferably involves:

1. Ball-milling under conditions to free fiber from attached rocky matter without completely fiberizing or opening the asbestos;

2. Maintaining high dilution in the ballmill to permit the fiber to be floated out of contact with the balls;

3. Effecting a separation of coarse rock and fiber while Wet;

4. Collecting long fiber short fiber 5. Compacting the fiber;

G. Drying the compacted fiber; and

7. Fiberizing the dried fiber.

In the accompanying drawing, forming a part of the disclosure, I have shown a preferred form of apparatus for carrying out the herein-described process of treating asbestos ore. The construction ofthe individual instrumentalities associated in the apparatus all being well known, and the purpose of the drawing being merely to aid in bringing about a clear understandingofthe processthe drawing is schematic and diagrammatic in character and the details of construction of the sepa separately from rate instrumentalities are not included there- 1n. Obviously, the process may be carried out by apparatus other than that shown, and the drawing is intended to be merely illustrative to aid in clarifying the process.

In this drawing:

Figure 1 is a schematic, somewhat diagrammatic, view in plan of a plant for carrying out the herein-described process; and

Fig. 2 is a similar View in elevation of the same.

In the ball-milling step, sufiicient water should be provided to effect a highly dilute and liquid pulp. It has been discovered that if asbestos ore is ball-milled under these conditions, the asbestos portion of the ore is detached from the rock and divided into a multiplieit'y of (so-called) pencils, or groups of fibers, which preserve to a considerable degree their original parallelism and length.

By the term pencils, as used herein, is meant groups of asbestos-fibers visible to the unaided eye, retaining substantially the original parallelism which they possessed in the ore, and of suflicient density when dried to be distinguished by their stalky appearance and resistance when compressed in the hand. If a thick pulp is made, as under usual ball-milling conditions, the fibers are thoroughly opened or fiberized, and in the latter condition are soft and readily broken up into short lengths. Although the specific gravity of the asbestos and the associated rocky matter are often the same, the pencils are found to be somewhat flattened, spaced apart, or composed of attached groups of pencils so that they may be floated off in preference to gangue matter. Preferably, a pool of water is maintained adjacent the means utilized for grinding the asbestos-ore; and the grinding means should be submerged therein. Such a pool of water should be relatively free from grinding media, and if situated above such grinding media, may be agitated to maintain the asbestos in a state of suspension.

By detaching as herein used, I mean the dissociation of asbestos from the gangue in a relatively unbroken state and of normal length.

By parting as herein used, I intend the expression in its broadest meaning, that is to say, in the sense of separation, division, or dissociation. When thus used, the term may include what in crystallography is tec nically known as parting and also what is technically known as cleavage. The expression parting, therefore, is intended to include, broadly, a separation substantially along the longitudinal lines of least cohesion of the fibers.

By the terms opened fiber and fiberized asbestos, as used herein, is meant asbestos which has been sufficiently separated into its individual fibers, or groups of fibers, that it cannot be distinguished as a pencil and possesses a so ft, wool-like, or silky feel.

By the terms fiberizing and opening, as used herein, is meant the function of separating to a greater or lesser degree asbestos into individual groups of fibers.

By the term excess of water as used herein, is meant water in sufficient quantity to form a watery, liquid pulp of sufliciently low density to permit floatable solids therein to migrate freely.

It is a concept of the present invention that the asbestos-fiber should be preserved as closely possible in its natural state as a relatively dense compact mass, while it is wet. Any fiber which is opened or fiberized to a substantial extent while wet is preferably compacted together in a mass and dried in such manner as will not substantially disturb the density of such compacted mass until the drying step is substantially completed.

It may be stated, therefore, to be one concept soft, fibrous portions and hard, dense, nonfibrous portions. The relations of the fibers to the rock varies with the products of different mines. In some, the fiber occurs in parallel veins separated by narrow bands of hard rock; in others the veins are irregular as to their relative direction and extend at all angles through the rock; and in other mines, the fiber may occur chiefly in slip planes of the rock, or in cleavage planes. In any case, there is usually associated with the ore large amounts of hard, barren rock, and economy of operation demands that this should be crushed only enough to detach the fibrous matter therefrom. Crushing in excess of this results in lowering the capacity of the bar-mill, or similar crushing unit, and placing additional duty on the separating units. Moreover, it has been found that, when pulverized, this hard rock is a contributing factor in the discoloration of the fiber. By using the well-known ball-mill of the so-called Marcy-type, for instance. this excessive grinding may be avoided and the hard, barren and unground rock be thus discharged from the mill and screened out of the circuit. In the present case, the pulp density, as stated, must be watery to such an extent as to permit the fiber to migrate freely in the liquid. It is customary in ball-milling practice to calculate the pulp density by the relation of ore fed to the mill to the water introduced therewith. Thus, in the case of the aforementioned Marcy mill, the pulp-density recommended is one part of ore to 0.3 parts of water. Catalogs of the manufactures state that the density may be as little as one part of ore to one part of water. These figures contemplate the reduction of ore to meshes ordinarily required in ball-milling practice, for example, eight meshes to the inch, and even finer. The fluid character of the pulp is, therefore, relatively dense. Such a condition would be detrimental in the practice of the present invention. It must be realized, however, as heretofore indicated, that a substantial part of the material in the present invention remains unground and is discharged from the mill in such state of massiveness that many individual pieces have dimensions as great as one inch or more. The discharged pulp may be regarded as falling into three classes, viz: fiber, rock, and sand. The rock-portion often amounts to fifty per cent to eighty per cent of the millfeed. Inasmuch as the rockportion sinks readily and is not maintained in a state of liquid suspension in the ball-mill, it cannot be regarded as increasing the density of the pulp to any substantial degree. Thus, I may use an amount of water which, under usual ballmilling conditions (in which practically all the product is reduced to sand and slimes), would form a pulp of relatively dense, viscous character; but which, under the conditions of my invention, would form a liquid pulp of low density. The pulp density is, therefore, determined by the relation in the ball-mill of water to fines. By the term fines is meant materiali capable of being sustained in liquid suspension under ballmilling conditions.

lVhen the asbestos-fiber has been detached from the rock and sufficiently treated by the milling-element (which in this case may be steel-balls) to enable the fiber to remain in liquid suspension within the mill, the function of the ball-mill is complete, and the resultant product should then be discharged from the mill as quickly as possible. Means for accomplishing a rapid discharge of heavy unground products are, available, for example, in the Marcy ball-mill. The coarser rock, such as that having a diameter greater than one-half inch, is preferably separated from the remainder by any convenient means, as by use of a trommel or grizzly having onehalf inch openings. This coarse rock (of plus one-half inch size) may then be rejected as worthless or may be retreated by subsequent crushing if found desirable.

The minus one-half inch product, contain ing the asbestos-fiber detached from the rock, is then subjected to a separating step in a water medium. This is preferably done by the use of a so-called Eastman-Dolbear separator. In practice, this last-mentioned ap aratus gives excellent results. All free fi )er and pencils are delivered over the discharge-weir together with some sand, while the tailings are free from fine fibers and may be rejected or be retreated by further crushing if found desirable. The overflow from the weir of the separator is then preferably subjected to a screening-operation. Preferably, there is used a punched metal screen having twenty meshes per inch of (i/64th inch diameter each, such (for example) as the soealled Dolbear rotary screen.

This screening-operation effects a substantial separation of the long from the short fibers. The treatment of the two products differs in many important respects: The long fiber, which then will have been substantially freed from fine sand, will have been collected and retained by the screen. The collected product may then contain water to the extent of two to four times its weight. This water may be removed in any convenient wa The water that is removed is that which 15 technically known as mechanical water, as distinguished from the water of crystallization normally present and chemically combined in the asbestos. I

It is desirable that the fiber shall be well compacted before it is dried and be maintained in compact form, or as a cake, until dried. After the cake shall have been suitably dried, it is fiberized or opened in a suitable manner to produce fiber of the character of the character desired. During this drying and fiberizing step, the long fiber is preferably prevented from receiving an admixture of short fiber. By this separate treatment, a long fiber of whiter color will result than can be produced by any process which permits the intimate admixture of the shorter grades during those steps. It is important that the fiberizing be accomplished in such a manner that the fiber-length will not be destroyed. To that end, an ordinary willower-comprising a horizontal cylinder with beating arms rotating therein and having feed and discharge means at oppositely disposed ends of such cylindermay be utilized for this purpose; but it will be important first to determine the proper speed of the rotating blades. the pitch and form of the blades. the proper clearance between the blades and the shell, and such other factors as may influence the products. This may be determined by tests. These factors may be utilized to control the character of the product produced. By slight fiberizing, a harsh product, containing a considerable amount of pencils, may be produced. this type of product being especially desirable in the manufacture of asbestos-shingles. By more intensive fiberizing, a relatively soft fiber may be produced, as required for spinning purposes or other uses. If much sand is associated with the fiber being treated, it may be found necessary to remove this sand frequently to permit the ready passage of fiber through the apparatus. After the long fiber has thus been prepared in this opened or fiberized condition. it may then be passed through graders, as is customary in asbestos-milling plants, to divide the fiber into products of various grades.

Reverting, then, to the shorter fibers and sand which have passed through the QO-mesh screen, this product in its state of high dilu tion in water may then be subjected to separation, dewatering. compacting, drying and fiberizing steps. The separating of fine asbestos from sand may be accomplished by useof overflow cones preferably about four feet in diameter and height. Cones of the wellknown Allen or Callow types may be used for this purpose. The overflow will be found to be fairly clean fiber, while the underflow of the first cone will contain sand and fiber. The underflow may thus be delivered to further cones until such underflow is sufficiently clean to discard. The overflow of the cones (containing fairly pure fiber) is then directed to settlers, which may be of the well-known Dorr type or settling cones. The fiber settles readily, thickening into a pulp of proper density for Oliver-filters, to which the pulp is then preferably delivered. The filter delivers a cake containing less than forty per cent moisture, and is usually in a relatively flat mass having a varying thickness averaging, say, one-half inch. The vacuum of the filter may be sufiicient in itself to accomplish the compacting step; but, if not, this may be effected by passing the cake through pressrolls or other suitable means. It has, however, been found preferable'to dry the cake in compact form to attain the best results. It is therefore desirable to dry the cake in a pan-conveyor type of drier through which the cake may be passed without destroying its form. \Vhen dried, the cake is then fiberized, preferably separately from the long fiber, whereupon it may be treated (in the manner usually employed in asbestos-mills) to remove any remaining sand and to divide it into grades or sizes suitable for the market.

In the embodiment illustrated in the accompanying drawing, the reference-character 1 designates an elevator by which ore, which has been previously crushed by any suitable and well known means, to pass through approximately a three-inch ring, is elevated to the storage bin 2 which is employed as a matter of convenience. The storage bin discharges near the bottom thereof, whereupon the ore is delivered by any suitable means, such as a belt conveyor 3, into the feeding mechanism 4 of the ball mill 5. Water is also introduced at this point.

The ore, having been suitably treated in the ball mill, is discharged upon the reciprocating screen 6 (Fig. 1) which is preferably of rather coarse mesh, such, for example, as that having perforations of an inch in diameter and of punched-metal construction. The oversize 7 (Fig. 1) from this screen may be either rejected or may be delivered to the ball-mill 8 for further treatment, if desired. The method of rejection or delivery is not shown herein, as it is not deemed necessary to illustrate details of a simple mechanical nature. 2

The material passing through the screen 6 isdelivered upon the apron 9 (Fig. 1) to an elevator 10 by means of a chute (not shown) which discharges into the distributor 11 whence the material is uniformly distributed to the separating machines 12 by means of conduits 13.

y The separators 12 deliver an overflow of water, asbestos, and, in some cases, sand, which is discharged into the launder 14 and thence to the distributing launder 15. feeding into the aprons 1G. The aprons 16 deliver this mixture to the surface of the rotary screens 17 in such manner as to retain the long fiber upon the surface of the screens while permitting water, shortfiber and sand to pass through the screens. A coarse product is also discharged into the launder 18 and is either conducted to waste or to re-treatment by means of the chute 19 connecting with the ball mill 8.

The long fiber is delivered by the screens upon the surface of a belt of wool felt indicated in the drawings by the number 20. This felt is travelling in the direction indicated by the arrows and causes the fiber and water included therewith to be subjected to compression by the compacting rolls 21 by which a substantial part of the water is driven off and the fiber formed into a compact cake. The fiber cake is discharged from the felt by gravity into the hopper 22 and thence into the drier 23 through which is moving, slowly, a pan type conveyor 24, which pan conveyor is moving in the direction indicated by the arrow in Fig, 1. Upon passing through the drier the material is discharged upon the conveyor 25 whence it is delivered, as shown in Fig. 1, to the fiberizer 26. From the fiberizer 26 the material is then transported by any suitable and well known means to screening devices in which the fiber is graded according to its length. These graders are standard in the art of treating asbestos fiber, wherefore it is not deemed necessary to illustrate them.

Referring again to the rotary screen 17, these screens are preferably of a fineness of 20 meshes to the inch and of punched material. While the long fiber is collected on the surface of this screen and subsequently handled as already described, the material passing through the screen consists of a mixture of short fiber, water, and, in some cases, substantial quantities of sand, the amount depending on the adjustment of the separators 12. This mixture of fiber, sand and water is collected in the launders 27 (Fig. 2) whence it is delivered to the pumps 28 and elevated into the classifying cones 29. In this cone a separation is made of the fiber and any sand which may be present, the sand being discharged by the hutch 30 (Fig. 2) into the launder 31 by which it may be conduced to waste.

The overflow of the cone 29 comprises a mixture of water and short fiber in a very dilute condition, the overflow being conducted by the launder 32 to the distributor 33 whence it is distributed to the settlers 34 by the pipes 35 (Fig. 2). The overflow of the settlers 34 is clear water which may be discarded or returned to circuit as desired, while the underflow of the settlers is conducted to the filters 36 by the pipes 37 (Fig. 2).

The filter cake is discharged upon the conveyor 38 moving in the direction indicated by the arrows at the end of which the material. is discharged upon the apron of the drier 23. This preferably also comprises a pan conveyor 39 (Fig. 2) by which the material moves through the drier 23 in the direction indicated by the arrow. The dried material discharges upon the conveyor 40, whence it is delivered to the fiberizcr 41 of Fig. 1. After it is discharged from the fiberizer, it may then be delivered to graders or may be bagged or otherwise prepared for shipment.

Referring again to the ball-mill 8, the material treated therein is discharged upon the screen 42which may be of somewhat smaller mesh than the screen 6, and the oversize therefrom may then be discarded as Waste. The undersize is delivered to the elevator 43 (Fig. 1) which delivers the material to the distributor 44 (Fig. 1) and thence by conduits 45 (Fig. 1). to the separators 46, thereafter the material is treated in the same manner as that distributed by the distributor 11.

In illustrating a. plant suitable for the practice of this process, it must be understood that I do not thereby limit my invention to the specific machines illustrated therein. The structural details of the machines are Well known or are such as would be provided by a mechanic skilled in the art. Similarly, it is not thought necessary to indicate in the draw ings such items as the source of power, pulleys, shafting, piping, etc.

The inventive-concept herein disclosed includes broadly and generically, the treatment of asbestos which involves the-reduction of the ore in any appropriate manner in a body of liquid to produce asbestos in pencil-like form and, then, subsequent treatment to effect a relatively complete concentration of the fiber and other treatment to produce and recover a valuable asbestos product. A particular manner of effecting reduction of the ore is by ball-milling in a body of liquid, thereby detachin the fiber from rock and separating the fiber by division along its natural lines of parting only, and this has been made the subect-matter of my companion application Serial No. 717,556, filed June 3, 1924.

What I claim is:

1. The method of treating asbestos ore which consists in reducing and separating the same in pencil-like form from associated rock.

2. The method of treating asbestos ore which consists in reducing the same in water, detaching asbestos in pencil-like form from associated rock, and efi'ecting separation of rocky matter from asbestos.

3. The method of treating asbestos ore which consists in reducing the same in water to detach the asbestos in pencil-like form from associated rock, and depositing such reduced ore in a body of water to effect separation of rocky matter from asbestos.

4. The method of treating asbestos ore which consists in reducing the asbestos to pencil-like elements in a liquid, and floating the fibrous portion out of contact with reducing media to recover said elements.

5. The method of treating asbestos-ore which consists in separating the fibrous portion in pencil-like elements from the rocky portion thereof in a medium of liquid, floating the fibrous portion out of contact with the detaching means, and subsequently efiecting a separation of the fibrous portion from the rocky portion.

6. The method of treating asbestos-ore in liquid, including a fiber-detachin step to produce asbestos containing pencilike fiber, and a concentratin step.

7. The method of treating asbestos-ore including, in sequence, a fiber-detaching step to produce'partly opened fiber, a concentrating step, a compacting step, a drying step, and a fiberizing step.

8. The method of treating asbestos-ore to recover the valuable portion thereof consisting of severing the fiber in pencil-like form from the associated rock merged in a. liquid, floating the fibrous portion out of contact with a severing means, producing a concentrate rich in fiber, compacting such concentrate, and submitting such concentrate to a fiberizing treatment followed by a screening step.

9. The method of treating asbestos ore, in-

cluding ball-milling the ore, and forming a I concentrate containing a substantial proportion of pencil-like asbestos.

10. Method of treating asbestos-ore, including ball-milling the ore in the presence of liquid, forming a concentrate of the asbestos, a substantial part of which comprises stalky masses of asbestos partly dewatering such concentrate, compacting the concentrate, drying the concentrate, and subsequently subjecting the dried concentrate to a fiberizing treatment.

11. The method of treating asbestos ore including ball-milling the ore in the presence of an excess of water until the asbestos is severed from the rock in stalky masses, thereby forming a partly-opened fiber product.

12. The method of treating asbestos ore including ball-milling the ore in the presence of an excess of water until the asbestos is severed from the rock in stalky masses, thereby forming a partly-opened fiber product, and subsequently subjecting the partlyopened asbestos to a fiberizing treatment.

13. The method of treating asbestos-ore, including treating the ore in water to detach the asbestos from the rock in the form of pencils, moving the asbestos pencils out of contact with the detaching means, effecting a separation of asbestos from intermingled rocky matter, recovering the asbestos, and

compacting and drying the recovered prodnot.

14. The method of treating asbestos-ore, including treating the ore in water to de ach the asbestos from the rock, in the form of pencils, moving the asbestos pencils out of contact with the detachingmeans, effecting matter While sub- 7 any division of fibers takes place substantially along the lines of partin only.

16. The method of treating asbestos-ore, including detaching asbestos in the form of pencils from associated rock matter in a liquid medium, separating coarse rock associated therewith, screening the remainder while wet to effect a separation of long fiber from short fiber, and separately recovering the lon fiber and short fiber.

1?. The method of treating asbestos ore including severing the asbestos from the ore in a medium of water and separating the fiber in pencil-like masses of natural length from the associated rocky matter.

18. The method of treating asbestos-ore, including reducing the ore in an excess of water, thereby detaching asbestos from rocky matter, concentrating the ore, screening the concentrate while wet to produce products containing relatively long and relatively short fibers, respectively, dewatering the products, and separately drying such products.

p 19. In the method of treating asbestos-ore,the steps of detaching the asbestos from rocky matter in the presence of water, effecting aseparation of asbestos from rocky matter in water, separating the asbestos while wet into divisions, one of which contains chiefly relatively long fiber and another of which contains chiefly relatively short fiber, treating one of the products in a medium of water to efl'ect a further concentration thereof, and drying the concentrated asbestos.

20. In the method of treating asbestos-ore, the steps in combination of detaching the asbestos from the rocky matter associated therewith, thereby dividing the asbestos into a multiplicity of pencils, concentrating the pencils in a. medium of water, separating the asbestos into divisions of different lengths, and treating the divisions separately to recover the asbestos therefrom.

21. The method of treating asbestos-ore comprising introducing the ore into a ball mill with water, detaching the asbestos from asosciated rocky matter, discharging .from the ball-mill a pulp containing asbestos-fiber present chiefly in the form of a multiplicity of pencils, together with rocky matter, separating a part of the rocky matter from the fiber, dividing the remaining product into divisions according to the predominant lengths of fiber present, subjecting each division to further concentration and to de watering, compacting, drying and fiberizing treatment, and recovering the asbestos.

22. The method of treating asbestos ore including crushing the ore only sufiiciently to sever the asbestos from the rocky matter associated therewith and avoiding reduction of the mass to integral or separate fibers.

23. The method of treating asbestos ore including crushing the ore only sufliciently to sever the asbestos from the rocky matter associated therewith and avoiding reduction of the mass to integral or separate fibers, and effecting a separation of the asbestos from the rocky matter in the presence of water. 24. The method of treating asbestos-ore, including ball-milling the ore in the presence of water to detach the asbestos, discharging the asbestos from the ball-mill in the form of pencils, and subsequently submitting the pencils to a fiberizing treatment so controlled as to vary the degree of fiberizing according to the product desired.

25. The method of treating asbestos-ore, including ball-milling the ore in the presence of water, to detach the asbestos from associated gangue, concentrating the asbestos while wet, compacting the concentrate by filtration, and drying the resultant filter-cake.

26. The method of treating asbestos-ore, including crushing the ore in the presence of water to sever the asbestos from associated gangue, concentrating the asbestos while wet, compacting the concentrate by filtration, and drying the resultant filter-cake in masses possessing in part their form when discharged from the filtering means.

27. The method of treating asbestos-ore, including severing the asbestos in pencil-like form from associated rocky matter in the 1 presence of water in sufficient volume and with sufiicient movement to effect the discharge of the asbestos chiefly in the form of pencils.

28. The method of treating asbestos ore including severing the asbestos fiber from associated rocky matter in the presence of water, concentrating the resultant pulp, removing mechanical water, and causing the fibers in such concentrate to be maintained in close contact until the mechanical water therein has substantially all been removed.

29. The step in the method of treating asbestos ore which consists in ball-milling the ore in the presence of suflicient liquid to maintan a mixture sufiiciently fluid to permit the subdivision of the asbestos along the lines of parting only.

30. The method of concentrating asbestos ore which consists'in treating the ore in the presence of a reducing element operating under Water, and causing the asbestos to become partly fiberized, that is, subdivided only along its natural line of parting and to rise while the rockymatter sinks.

31. The method of treating asbestos ore which consists in treating the ore in a reducing zone situated under water, reducing and subdividing the asbestos along its natural lines of parting only to preserve its natural length'and render it stalky in character, causing the resultant mass to be immersed in a body of water and maintaining it therein out of contact with the reducing zone, and separating the fiber from the rocky matter.

32. The method of treating asbestos ore which consists in subjecting the same to the action of freely-movable rolling elements operating in a mill in which a body of water is maintained, subjecting the ore to the action of the freely-movable rolling elements until the asbestos is subdivided only along the length of the fibers, and separating the rocky matter from the fibrous portion of the ore.

33. The method of treating asbestos ore which consists in reducing the ore in a fluid, maintaining a body of fluid separate from the reducing zone causing the asbestos to become detached from associated rocky matter, by dividing it along its natural lines of parting only whereby its natural length is preserved and the resultant mass is non-pulverent, then passing the resultant mass into said body of fluid and removing the asbestos and the rocky matter separately.

34. The method of treating asbestos ore which consists in treating the same in a body of water by rolling elements, subdividing the asbestos substantially along the length of the fibers only, floating the fibrous portions of the mass away from the rolling elements, and recovering said fibrous portions.

35. The method of treating asbestos ore, to separate its fibrous and rocky components, which consists in maintaining a relat vely large pulp dilution while detaching the asbestos from rock bya crushing action effected in a body of liquid whereby the fiber is divided along its lengthwise lines of parting only to render the same non-pulvcrent and to preserve its natural length, and separating the fibrous from the rocky components.

36. The methorT of treating asbestos ore, to separate its fibrous and rocky components, which consists in producing a relatively large pulp dilution by a crushing action efl'ected in an excess of liquid and thereby effecting a division of the fiber along its natural, lengthwise lines of parting only, liberating the fibrous from the rocky component, and effecting a discharge of relatively coarse material away from the valuable portion of the mass.

37: The method of treating asbestos ore which consists in reducing the same in a body of liquid and thereby effecting division of the fibcr along its natural, lengthwise lines of parting only to preserve the natural length of the fiber, maintaining valuable portions of the mass out of contact with other portions thereof, and elfecting a recovery of the fibrous components of the ore.

38. The method of treating asbestos ore to separate its fibrous and rocky components, which consists in subjecting the same to the detaching action of rolling elements in a body of water, maintaining portions of the mass within the zone of action of the rolling elements, elfecting displacement of des rable portions of the mass away from the action of the rolling elements, and then recovering such desirable portions.

39. The method of treating asbestos ore to separate its fibrous and rocky components, which consists in treating the same in a body of water within the zone of action of rolling elements, cascading said rolling elements to produce an intermittent surging action, suspending the fibers awa from the rocky ma material to limit the subdivision thereof substantially to the lines of parting only and discharging said fibers by impulse resulting from such surging action.

40. The method of treating asbestos ore, which consists in detaching fiber along its natural lines of parting from the ore in a liquid and, at the same time, preserving the natural length of the fiber, and then separating the fiber from the rocky portion of the ore.

41. The method of treating asbestos ore, which consists in cascading reducing elements in water containing asbestos until asbestos fibers substantially unimpaired as to length and subdivided along the lines of parting only are produced.

In testimony whereof I afiix my signature.

SAMUEL H. DOLBEAR. 

